Housing configurations for mobile phones are becoming more diverse each year, and there exists a variety of modes of use depending on differences in the housing configuration, and the like. Among them, two kinds of types are currently wide use: the straight type, which is used in the same mode across all of calls, data communication, and standby; and the foldable type, which is used by opening the housing during calls and data communication, and by closing the housing during standby. In addition, recently, the communication speed of mobile phones has become faster, and mobile phones that are capable of receiving such visual data as videos, video phone calls, one-seg broadcasts and the like, are beginning to grow popular. Because the majority of visual data is displayed in horizontally long (wide) manner, we are beginning to see mobile phones with housing configurations that enable making the display screen of the mobile phone display as a horizontally long screen when users are viewing visual data.
FIG. 1 is a diagram showing an example of the housing configuration of a mobile phone that is capable of horizontally long screen display when visual data is viewed, and is a diagram showing a configuration example of a mobile phone comprising a helical antenna. The housing configuration of the mobile phone in FIG. 1 is such that a first housing 101 and a second housing 102 are rotatably connected via a hinge 104, a third housing 103 equipped with a substantially rectangular display portion 106 is connected to the second housing 102 with a rotation mechanism portion 105 that rotates in a plane that is parallel with respect to a housing surface thereof, and the housing configuration comprises two display modes, namely, mode (A) in which the display portion 106 displays in a vertically long manner through the rotation of the rotation mechanism portion 105, and mode (B) in which it displays in a horizontally long manner. Thus, when displaying such visual data as videos, television (hereinafter abbreviated as TV) images and the like, it is possible to change readily to horizontally long display by rotating the third housing including the display portion 106 by 90°. FIG. 1 is a diagram showing the condition of vertically long display (A) and the condition of horizontally long display (B) viewed from a direction from which the display screen of the display portion 106 is visible. Of the housing configurations for mobile phones mentioned above, with respect to mobile phones of the foldable type or mobile phones with the housing configuration shown in FIG. 1, the housing is opened/closed and rotated in accordance with the user's mode of use. With respect to the foldable type in particular, because the reception characteristics of the antenna during calls and data communication (the mode in which the housing is opened) are different from those during standby (the mode in which the housing is closed), solutions for improving antenna characteristics in accordance with the mode of use have hitherto been proposed
In Patent Document 1 mentioned below, there is disclosed a technique for improving antenna characteristics during calls and data communication (the mode in which the housing is opened) for mobile phones of the foldable type. In addition, in Patent Document 1, there is also disclosed an antenna configuration for improving antenna characteristics during standby (the mode in which the housing is closed) for mobile phones of the foldable type.
[Patent Document 1] Japanese Patent Publication (Kokai) No. 2006-41899 A